Check out this seller if you are contemplating a supercharger for a 4.2....comes off a rover, but supercharger unit is the same as jaguar....even get the rover intake and induction elbow....i just bought the bare m112 from them for 300 delivered....beautiful rotors....i will re bearing and have a sweet unit....ebay item 233603747247....just wanted to post as an fyi....by the way he has 2 units listed

 

Decent price with all supporting parts. If I didn't have several spares, I would purchase another one. I would rather put the money into a KB twin screw upgrade, unless I needed a stock one to replace one with problems.